An automatic analyzer spectrally separates light, which has been transmitted through a liquid mixture of a sample and reagent, using a spectroscope, and receives light components from the spectroscope by a photo detection unit. The light components from the spectroscope have different wavelengths depending on physical positions. The photo detection unit has a plurality of photo detectors. Respective photo detectors receive light components related to wavelengths according to their locations.
The photo detectors are often deviated from their original positions at the time of assembling or the like of the apparatus. Such deviations are called wavelength accuracy deviations. When the wavelength accuracy deviations have occurred, position adjustments of the photo detectors are executed. However, the position adjustments of the photo detectors impose a heavy load on the assembler.
It is an object to provide an automatic analyzer which can reduce a load on position adjustments of photo detectors.